There has hitherto been known a clutch that couples a front cover, which serves as an input member coupled to a crankshaft of an engine, and an attachment portion, which serves as an output member coupled to an output shaft, to each other and that decouples the front cover and the attachment portion from each other (see Patent Document 1, for example). The clutch includes: a flange member coupled to a cylindrical connection portion formed on the front cover; a plurality of clutch plates (mating plates) fitted with a clutch hub fixed to the flange member; a plurality of clutch disks fitted with a clutch drum coupled to the attachment portion via a damper mechanism; a piston member that is disposed between the front cover and the flange member and that is movable in the axial direction to press the clutch plates and the clutch disks; and a return spring disposed between the front cover and the piston member. The clutch disks of the clutch are each a two-sided friction plate in which a sheet-shaped wet friction material is bonded to both surfaces. The clutch plates and the clutch disks are supplied with working oil for lubrication and cooling from a hydraulic control device via an in-flow hole formed in the attachment portion and a communication hole formed in the flange member. The working oil having passed through the clutch plates and the clutch disks flows around the damper mechanism etc., and thereafter is discharged to the hydraulic control device via an oil passage that does not communicate with the in-flow hole of the attachment portion or the communication hole of the flange member.